YouTube blocked our channels without reason!

Hello!
Me and my wife filming videos for our YouTube channels for almost 5 years. We are full-time youtubers — YouTube is our life. We film videos every day for several hours. We got ~50 youtube channels — about all topics in which we are interested in our life. Among our channels is ‘Shkola Bloggera’ (translation from Russian — «Blogger’s School») — https://www.youtube.com/shkolabloggera , biggest Russian-speaking resource about YouTube (93.000 subscribers). All our channels got ~350.000 subscribers total.
Week ago 37 of our channels with good reputation (each of them <6000 subscribers) were blocked without any reason (we even didn’t get any emails about strikes). All other our channels which got >6000 subscribers wasn’t affected and still active.

All our channels got useful and kind videos, for example, among blocked channels there is ‘AgroPrognoz’ ( https://www.youtube.com/agroprognozru ) – the biggest (1700 subscribers, a lot for such community) Russian-speaking YouTube channel about agriculture and soil science. There are absolutely no reasons to block it. Also it’s strange that our other, English-speaking channel about soil science – ‘SoilMap’ isn’t blocked ( https://www.youtube.com/channel/UCsniV3tyDTOU8cTUP2SMTJg ).

This block is somekind of error. We follow community guidelines very carefully and we do not have any forbidden content at our videos. We do not spam and do not make illegal actions. Also we do not have any videos with children (we do not have children).

Finally, please notice, that all our ‘big’ (6000+) YouTube channels are still active and have good reputation, only channels with <6000 subscribers were terminated; but we equally follow YouTube rules and guidelines at all our channels — small and big-ones. So it is certainly an error.

Just some more information about us to explain why we have so many channels. We are artists and make a lot of different stuff like painting, writing books, playing musical instruments. At the same time we are very active in sports, we like to travel a lot. That’s why we made decision to start a lot of YouTube channels. Also a few facts about us:
— we both are PhD in Biology and authors of 20+ scientifical articles (our last scientifical works were about YouTube). We are authors of two science books and planning to write one more soon — about YouTube (based at experience of our channel about blogging — https://www.youtube.com/shkolabloggera )
— we work as web-developers and graphical designers
— sometimes we writing not scientifical articles to different magazines and newspapers (about games, ecology & etc). Also we started to write fiction books. Example — http://shtukensia.com/thisis/mybooks/office/
— I’m musician, rock band leader, guitar teacher (my channel ‘Gitarka’ — https://www.youtube.com/gitarka got 50.000+ subscribers). Also I’m dj and I write electronical music.
And it’s not everything… That’s why we have so many YouTube channels. Each channel is unique for us and dedicated to specifil topic from our life.

Please help and report this problem to programmers at Google! This isn’t typical problem, it could happen again and again with innocent people! Please help us to restore our youtube channels!